Method of charging a conductor and induction - Param Himalaya
A material can be electrified or electrically charged if some charge is given to the material or taken out of the material.
Ordinarily a body is said to be electrified or electrically charged if it has excess electrons or it is deficit of electrons.
In fact , every neutral objects consists of positive and negative charges which are equal and opposite in polarity , so net charge on the neutral objects is zero.
Net Static charge can exist on an object in the following ways :
1. Charging by physical contact / Electrification by conduction :
if an uncharge conductor is touched with a charge conductor, the uncharge conductor may acquire charge similar to the charge conductor.
It happens because some of the charges are shared at the point of contact of the conductors.
2. Charging by friction / Frictional Electrification :
The electrostatic charges ( i.e , charges at rest ) developed on insulating bodies when they rubbed against each other is called Frictional electricity.
One of the rubbed material loses electrons and become positively charged and the other material gains these electrons and becomes negatively charged.
No new charge is created in the process of rubbing of materials.
3. Charging by induction :
It is the process of charging a neutral conductor by placing it near or close a charged object is known as charging by induction.
A charged body is brought close to the uncharged conductor but does not touch it.
This method of charging is known as charging by induction because no physical contact is made between the charged and uncharged bodies.
Inducing charges : The charges on a charged body which give to charges on another uncharged body without any physical contact are known as inducing charges.
Induced charges : The charges appearing on the uncharged body by the process of induction are known as induced charges.
Induced charges on a body are of opposite sign to that of inducing charges. For example , if inducing charges are positive , then induced charges are negative and vice-Versa.
A non-conducting body can also be charged by induction under suitable conditions when the inducing body carries heavy charge or the non-conducting body suffers from abnormal temperature conditions etc.
Certain insulators i.e dielectric also show behaviour similar to induction known as POLARIZATION. When dielectric is placed in an electric field , induced charges appear on the surface of the dielectrics.